Pulsatile tinnitus

Pulsatile tinnitus

What is pulsatile tinnitus?

Tinnitus is the awareness of sound by a patient in the absence of an appropriate external source. Pulsatile tinnitus is a symptom that relates to any condition causing a person to hear a sound synchronously with their own heartbeat. Pulsatile tinnitus usually has a source and is, therefore, an appropriate awareness by the patient. In most cases, the pulsatile tinnitus or bruit is caused by a vascular problem, not an ear problem. No matter what the sound’s characteristics are, it usually follows the patient’s heartbeat and pulse. A venous hum is a continues sound reinforced by transmitted arterial pulsations and may also present as pulsatile tinnitus.

Pulsatile tinnitus
A persistent stapedial artery may cause a pulsating tinnitus.

How common is it?

Pulsatile tinnitus is not that common, estimated to occur in about 3% of patients suffering from tinnitus. It can be very distressing to patients, and despite usually not being serious, it may be indicative of a potentially serious condition and therefore needs to be investigated.

Most often, pulsatile tinnitus is caused by blood flow disturbances in the head and neck.

Why should it be investigated?

Pulsating tinnitus can create a lot of anxiety, and patients are often concerned that there is something about to “burst” or “blow up” in their head. Although this condition is usually not life- threatening, it may be associated with serious conditions and therefore always require investigation.

What are the causes of pulsatile tinnitus?

Some of the most common cause include:

  • Hyper dynamic circulation as is found in patients with high blood pressure, a hyperactive thyroid, pregnancy, Paget’s disease and anaemia.
  • Venous sinus stenosis
  • Idiopathic intracranial hypertension (IIH)
  • Paraganglioma
  • Atherosclerosis of the arteries
  • Aneurism, arteriovenous fistulae and malformations
  • Persistent stapedial artery (a rare congenital abnormality where an artery that should disappear persists).
  • Vascular loop syndrome
  • Intracranial tumours such as acoustic neuroma and meningioma.
  • Temporal bone abnormalities such as superior canal dehiscence SCD and dehiscent jugular bulb.
  • Arnold- Chiari malformation, fibromuscular dysplasia and venous diverticula.
  • Middle ear effusion
Pulsatile tinnitus
Narrowing or stenosis of the venous sinuses (segment between yellow arrows), is an underdiagnosed cause of pulsatile tinnitus.

What are the possible mechanisms?

The mechanisms by which it can occur include:

  • The acceleration of blood flow which disrupts the normal laminar flow, converting it into audible turbulent flow.
  • The amplification of normal sounds due to conditions of the inner that increase bone conduction
  • The impairment of sound conduction leading to reduced masking of external sounds
  • A hyperdynamic circulation

Pulsatile tinnitus and hearing loss.

The same condition causing the pulsatile tinnitus may also cause hearing loss. Pulsatile tinnitus per se may also lead to hearing loss which will resolve if the tinnitus is treated. In fact, a patient should have an adequate hearing in at least one ear to appreciate the tinnitus.

Rhythmic non-pulsatile tinnitus.

This periodic sound is not in sync with the heartbeat. It is usually not vascular but still needs to be investigated. Middle ear myoclonus (MEM) and palatal myoclonus occur due to myoclonic contractions of certain muscles.

Pulsating tinnitus
Myoclonus of the middle ear muscles may cause tinnitus.

Examining patients with pulsatile tinnitus.

A comprehensive medical history is obtained, focussing on the tinnitus characteristics and confirming that it is pulse synchronous, following the heartbeat. Certain medical conditions may lead to a hyperdynamic circulation and need to be explored. Medication such as hormones, calcium antagonists and ACE inhibitors can cause pulsatile tinnitus. A history of trauma, pain, sudden onset, headaches, local tenderness, visual disturbances, pulsing vessels behind the ear and nausea and vomiting are “red flags” and should be thoroughly investigated.

Patients may report that certain activities such as turning the head, gentle pressure on the vein or holding the breath whilst bearing down (Valsalva manoeuvre) may change the tinnitus’s loudness and even make it disappear temporarily.

The medical examination includes a blood pressure reading, body mass index determination, fundoscopy, besides full head and neck examination. Otoscopy may show a pulsating mass behind the intact eardrum. Careful auscultation of the head and neck with a stethoscope and the unaffected side is of vital importance. Performing certain manoeuvres may help to distinguish between mainly arterial and venous causes.

Tinnitus is subjective if only the patient can hear it. Objective tinnitus is tinnitus that can be heard by the examiner. In some cases, it is so loud that it can be heard without a stethoscope. If the examiner cannot hear the pulsatile tinnitus, it does not mean that it is absent.

Special investigations may include blood tests, ultrasound examinations of the head and neck and cardiovascular system, hearing tests, lumbar puncture and imaging. Magnetic resonance imaging with gadolinium contrast administration and flow studies examines the choice to diagnose venous sinus stenosis and other vascular disorders. Computed tomography (CT) and computed tomography angiography (CTA) help evaluate the temporal bone and vascular variants such as a persistent stapedial artery.

As a final investigation, digital subtraction angiography (DSA) may be required and still remains the gold standard of investigating the vascular system. In the majority of cases, however, it is not necessary.

In 20% of cases, the cause of the pulsatile tinnitus cannot be determined.

Pulsatile tinnitus
A persistent stapedial artery (yellow arrow) seen on a computed tomography (CT) scan.

How is pulsatile tinnitus treated?

Pulsatile tinnitus rarely resolves on it’s own.

The treatment depends on the cause. Medical conditions should be addressed, and if medication may play a role, it should be substituted. In some cases, medical treatment with anti-hypertensives and medication reducing cerebrospinal fluid production (CSF) may help. Surgery or radiotherapy may be indicated to treat temporal bone abnormalities and tumours.

Interventional radiology is a specialised radiology division where trained radiologists utilise imaging techniques such as angiography in real time to place coils and stents in bloodvessels and embolise tumours.

The psychological effects of tinnitus are often overlooked. Tinnitus retraining therapy (TRT) and cognitive behavioural therapy (CBT) may help this regard.

It is advised that patients suffering from pulsatile tinnitus should consult with an ear- nose-and throat (ENT) specialist.

A support group for patients suffering from pulsatile tinnitus can be found at http://www.whooshers.com.